In most DSLR cameras there are 4 popular modes where exposure decisions are either fully or partially made for you by the computer in the camera. Those 4 modes are…

Full Auto – Green: where the camera chooses everything for you. You will certainly make a picture, but usually not with the best results possible.

‘P’ or the Program mode: where the camera chooses the exposure for you. Your camera will set the shutter speed and the lens f/stop to make a picture and this is a good all-around mode in which to shoot for everyday photography.

‘Tv’ or ‘S’ is for Time Value or Shutter mode: where you set the shutter speed and the camera assists by selecting the lens aperture appropriately to make a good exposure. A fast shutter speed can be a good option for freezing action to reduce motion blur when shooting moving subjects.

‘A’ or Aperture value: where you choose the lens f/stop or Aperture and the camera assists by selecting the appropriate shutter speed (time) to collect light to make a good exposure. Aperture mode is best for doing still life, portraits and for those times when you want or need to control the depth of field or the selective focus in a scene.

Tricking your camera

There is a fifth way where you can trick most new DSLR cameras to assist with the exposure, which can help you make your best shot.

The Manual mode is usually where you make ALL of the exposure decisions in your camera, including the light sensitivity or ISO. By setting the ISO to Auto you can force your camera to assist with the exposure based on your Shutter and Aperture settings and on the available light in the scene. In Manual mode you can set the shutter speed, to freeze the motion as desired, and set the lens aperture to get the selective focus or depth of field that you want all while letting the camera figure out the proper ISO to make a good exposure.

Here is an example – you are going on a whale watch and want to come back with sharp images, but you are on a moving boat and the subject matter is moving as well. Here’s what you do…

Select Manual mode in your camera and set the shutter speed to a fast setting – 1/1000th to 1/2000th of a second for instance. Most lenses have a sweet spot where their sharpness is the best, usually between f/8 and f/11. Set the aperture in this range favoring f/11 to get the sharpest image from your lens and to also gain more depth of field. Next, set the ISO to ‘Auto’ and let your camera assist by adjusting the light sensitivity accordingly. These settings work best in areas with bright sunlight. In darker scenes, the ISO may be raised too high causing noise in the picture that will manifest as grain. This ‘Auto-Manual’ or ‘Manual-Auto’ technique also works well for photographing birds, surfers, and other moving subjects where you want to have the ability to control the sharpness of the image.

Give it a try the next time you are out photographing and see if it helps you to make your best shot.

— Text and photo: Michael Leonard